Warhammer 40K: Heralds of Doom
by Larry The Mailman
Summary: In the grim darkness of the forty-first millenium, there is only war... and war has become much more drastic. Suffering from xenos incursions and attacks from the Ruinous Powers of Chaos, who, or what, could possibly make the Imperium more scared of its position that it is now? :: Rated M due to self-explanatory reasons.
1. Dawning of a Horror

In the grim darkness of the forty-first millenium, there is only war. With the **Imperium of Man** still reeling from the _Twelth Black Crusade_ led by **Warmaster Abbadon the Despoiler**, leader of the forces of the **Ruinous Powers of Chaos**, numerous xenos forces took it as a sign to increase their attacks upon the newly fractured Imperium. Yet, many more plan the same, and alas, only the Imperium knows of it, and prepares for it.

Reports of unrest came from the _Segmentum Obscurus_, inciting the valiant forces of the Imperium to put an end to them, and then turn to other issues. These reports were that of **Orkish** incursions upon the Imperium's borders, attacking several Agri-Worlds and a singular Forge World, whilst attempting to reach a Hive World guarded by the Imperial Navy. Their first destination would be the Hive World of _Scintilla_, located within the _Calixis Sector_, to support the defense of the planet, which was, although ready at the least in orbit, woefully unprepared for the horrors of Orkish combat.

As the ship left the Warp, it's brilliance and magnificance showed once more to the Imperial Navy. It was a Gloriana-class Battleship, ordaned with blue paint, a golden eagle on the front and gold as far as the eye could see. There was no spot where there was not at least a speck of gold, and even if there was, nobody would notice, either due to their awe, or due to their deaths at the hands of its cannons. As the ship came into a position most optimal for the planet's defense, it was contacted from the surface by their brothers-in-arms, the fabled **Iron Fists** of the **Legio**** Astartes**, the Emperor's wrath.

"Hail to the _Macragge's Honour_, brother **Guilliman**."

"Hail to the _Phalanx_, brother **Dorn**."

"What brings you into the Segmentum Obscurus? I had sworn that you were in the _Segmentum Tempestus_ and that you would not return for another few centuries."

"So I had thought as well, brother. But Father has replaced me, insisting that I be here and help you with cleansing the Segmentum Obscurus of immediate threats."

"So it would seem. Father has had many reasons for his actions, and I am sure there was one behind this choice, as well."

"Indeed. But enough of Father, what are the defenses of this planet, and when can we expect the Orks to strike?"

"The planetary defenses on the ground are quite formidable, with numerous Land Raiders to support our fellow Space Marines and Imperial Guardsmen, alongside artillery, defensive fortifications, three companies of the Death Korps of Krieg, one company of Vostroyan Firstborn, and twenty companies from Cadia. We are also expecting the Adeptus Mechanicus to arrive before the attack begins. But as for the defenses in orbit, that is where we are critically weak. With only five Dauntless-class Light Cruisers and seven Tempest-class Strike Cruisers, the planet's orbit is virtually undefended. I would have came with the Phalanx, but it was tied down by repeated attacks of traitors, and the Mechanicus ships are still ways from here. However, with your ship here, I believe that the Imperial Navy could hold out long enough until the Adeptus Mechanicus ships arrive in the case of their delayed coming."

"Thank you brother, for sharing this information with me. It will prove most useful for the coming battle. Expect five hundred of my finest to aid you in battle on the ground should the enemy land. They will be of invaluable use to you."

"Indeed they shall. I suppose it is time to make final preparations, for the Orks come in five standard hours."

"Agreed. Contact me if anything changes. I shall do the same for you."

"As you say, brother. Vigilanti semper manere frater."

"Tu quoque, frater."

* * *

Hours earlier, before the fateful meeting of the two Space Marine Primarchs, Roboute Guilliman and Rogal Dorn, the Emperor of Mankind, leader of the Imperium of Man and saviour of man, along with his loyal guard, his most elite, the Legio Custodes, were travelling to the ends of the Segmentum Tempestus in search for something that disturbed the wise Emperor. Two planets have been cut off from the Imperium, and he feared that the worst has happened. If his suspicions were confirmed to be true, then the Imperium would need to mobilize everyone it can, and deal with the threat. But as it stands, it could simply be Chaos, or even the vile xenos known as the Tyranids, a hivemind species hellbent on devouring the galaxy. As the Emperor looked out into the void of space, having left the Warp minutes ago, he turned around to face one of his most trusted, most elite, and deadliest of warriors, whom had wore brilliantly ordaned golden armour, to reflect his status.

"Captain-General Valoris, how much longer until we reach the planet?"

"Not long, my Emperor. We expect to arrive in twenty minutes, shipboard time."

"Good. Make contact with the **VI Legion**, and tell them that they are needed by I. No matter who we encounter here, I fear that the Custodes and I would not be able to last long on our own."

"As you say, my Emperor."

Putting his left arm unto his chest, the Captain-General left as to send word for the VI Legion - the **Space Wolves**, and their Primarch, **Leman Russ**. Whilst occupied by the Emperor's command, the Emperor himself continued to stare at the endless void, slowly seeing the planet that grew with each passing moment as his ship, the _**Bucephelus**_, crept ever closer. But as it came ever closer to the planet, it came under xenos attack. Small crafts going faster than most Imperium starfighters, probing the defenses of the Bucephelus, with only one of the twenty xenos fighters breaking off from the main group after dodging three cannon shots that only _Aeldari_ vessels could dodge with such ease. One of the other Custodes, a Shield-Captain, had interrupted the Emperor's moment of peace despite the gunfire, as to report the grave news.

"My Emperor, forgive me for disturbing you, but I have identified the xenos alongside the Adeptus Mechanicus Archmagos. They bear **Universal Union** signatures."

"These are most grave news. Shield-Captain Kalim Varanor, tell the pilots to take-off momentarily, inform every crew member to stay on full alert, and tell the Archmagos to scan for any Realspace ruptures that these xenos attempt to use. They shall not live to see the end of this day."

"As you say, my Emperor."

As the Shield-Captain left, the Emperor continued to stare into the void, thinking about the approaching dawn of the _Fifth Grand Invasion_ of this powerful xenos race. Alas, his concentration was disrupted as he saw one of the xenos crafts hover directly in front of him, only separated by glass. The craft had elegance, the smoothness of its build would make even the Aeldari jealous. Standing at around three meters tall, and seven meters long, it had a design similar to that of an organic avian without its wings. The craft was organic underneath that pitch black metal, and the Emperor knew it. These xenos utilized other races' strengths, and forcefully improved them for their own cause. They sickened him, but intrigued him at the same time. His deep thought was once more disturbed by the same craft exploding, making the Emperor hear a mere four seconds of its near daemonic screech, in spite of the laws of science forbidding sound from travelling through space. The explosion did little to damage the glass, but it did make the other craft quickly move over to its remains, blasting away at the remains in the hopes of leaving absolutely nothing for the Adeptus Mechanicus to study. Before the Imperium's finest fighters, the Primaris-Lightning Strike Fighters could be deployed, the xenos already destroyed the wreckage, and were now entering an engagement with the best pilots of the Imperium, handpicked by the Emperor himself, to accompany him on his journey to unite the galaxy. This engagement reminded him of how woefully unprepared the Imperium was in the waking hours of the _**Solaris Expeditionem**_ \- The Solar Expedition, which took place near the very end of the dreaded _**Horus Heresy**_.

* * *

**Yes, I am crazy. I am starting yet another fanfiction.**

**I have an obsession with the Combine, don't I? Well, it matters not, for I have given them tech and units I conceived in my own spare time.**

**How did the Emperor survive? Well, find out in the next, and longest chapter in the first ten chapters of this fanfic, for this was merely an introduction.**

**Expect me to publish a new chapter of The Light of Remnant in a week or two. As for Vandread: Second Incursion, give me a week or two as well. I'm really not feeling good right now.**


	2. 10,000 years ago, there was the Combine

In the thirty-first millenium, there is uncertainty, and war. The forces of Chaos Undivided have corrupted the Emperor's son, **Primarch Magnus the Red**, and deluded him into destroying the Emperor's most important project up-to-date: the _Human Webway_. Releasing waves upon waves of horrific daemons unto Terra itself through the Webway Gate, the Imperium has called upon its every subject who could, to come to Terra's defense against the daemon onslaught. But some of those who came, came with no intention of protecting the Emperor's home world, and the cradle of humanity. These traitor legions, being the XX Legion, IV Legion, XII Legion, XVII Legion, III Legion, XIV Legion, XV Legion, VIII Legion and the fabled XVI Legion - **Sons of Horus**, led by the archtraitor **Horus Lupercal**, son of the Emperor, and Warmaster of all the traitor legions. As battles raged on Terra's surface, and in orbit, a far more sinister force creeps towards the Imperium's capitol, as a far bigger consequence of Magnus' meddling, a consequence not even the Chaos God **Tzeentch**, the Changer of Ways, could predict.

* * *

The strange machinations of the Universal Union marched forth in conquest, world after world, galaxy after galaxy, dimension after dimension. None provided opposition at first, until rebellions started. But rebellions could be crushed, and the Union did not waste its time. In one of the collosal monolithic towers known as Citadels, lived a singular Advisor, a Shu'Ulathoi. His only job, for all of eternity, was to orchestrate invasions for this inter-dimensional Empire, by locating Portal Storms, storms which rocked planets and destroyed infrastructure, and proved potent for portal maintenance, locking onto them, and forcefully ripping open a portal through which invasion forces could flood through, and bring forth an age of darkness. Inside the control room for the **Tunneling Entanglement Device**, the device responsible for portal creation, the Advisor noticed something... strange. The power-up sequence had begun moments prior to him noticing, prompting him to believe it to be a visual glitch, something to repair later. Alas, as he saw the Tunneling Entanglement Device burst to life with its initial low hum, with streaks of Dark Energy beams coming from down below, it started worrying him. Who, what, and why. He left nothing to chance. Contacting his superior, he explained the situation in great detail, and kept telling his superior, even as he was headed his way, in which stage of activation the Tunneling Entanglement Device was. Having entered the sixth activation stage, his superior, the **Head of Union Security**, decreed that he would not arrive on time, and assembled a preliminary scouting force to investigate what on the other side could instigate the device to power-up on its own will. Once assembled, and the portal open, the horrific forces of the Union, known also as the Combine Empire, went through.

A total of eighty **Gunships**, thirty-five **Tylox-class Heavy Fighters**, one hundred **Dropships** and seven **Heavy Dropships** went through, and what they saw was a sight for their sore eyes: combat. Glorious combat, of proportions seen rarely in their lives, if ever. The battling forces of these unknown humans did not pay mind to them initially. Not when they were hiding amongst the tall buildings, not when they were landing, and not when they were unloading troops. No, they were detected only when all of the troops left the one hundred Dropships, four hundred of them Combine **OTA Elites**, with the remaining Dropships having supplements of **Striders**, tall synth creatures designed for sieges on occupied worlds, and as scouting forces. Fifty of them were released from the Striders, and their menacing howling alerted the citizens that were running scared from tall men in black armour, reminiscent of the Combine's Altrion Walkers, which could very well pass off as these tall men in black. Three citizens ran in the direction opposite of them, with only one of these men chasing them, stopping at the sight of a singular Strider. He was dumbfounded. Was this a machine of the false Emperor? Would he stoop so low as to allow xenos to defend Terra? His questions would go unanswered, as he dodged bullet after bullet, only to get totally disintegrated by the Strider's cannon shot. But alas, that Chaos Space Marine was in turn followed by Space Marines hailing from the VI Legion. As they crept around in stealth, they noticed the three-legged construct that was the Strider, and spoke silently.

"What in Fenris' name is that thing?"

"Xenos? Here? I've never in a million years expected xenos here..."

"Where'd that traitor go, anyway? I'm bloody sure he didn't ally with these blasted xenos."

"We should inform our brothers, get us some back-up."

* * *

"Augmented non-citizens in area. Performing sector sweep."

"_Affirmative. Report unusual findings immediately. Over._"

"Copy that, Overwatch. Sending ghost-drop to area of energy radiation, over."

"_Copy. Converge on energy radiation 10-20 on-foot. Out._"

The Heavy Dropships lifted off not long after, with the Tylox-class Heavy Fighters escorting them to their destination, leaving the ground forces to make their way on-foot. The forces marched on, the 400 Elites spread out to cover the whole perimiter around the convoy, as 25 Striders strode over the citizens who were scared, shouting words like 'Xenos!' and 'May the Emperor slay you!' Whoever this Emperor was, the people looked up to him in their time of need, which prompted the troops to send their report back to Overwatch, as to relay it to the Overworld in order to take appropriate action.

The soldiers immediately noticed that their weapons were hardly effective, and that the heavy-lifting and fighting was done by the Striders most of the time, if not always. One of the Elites contacted Overwatch, and made a formal request to requisition alien fire-arms so as to increase combat effectiveness from a meager 5% to around 170%, a total of 165% combat effectiveness increase. The request was accepted after a minute of formulating an answer to a question that was so rarely asked, causing one of the Elites to disintegrate his weapon by overloading it, and grab one of the guns from a dead adversary's cold, metallic hands. Checking the reload mechanism, he noticed that it was similar to the one they used, which meant that was no longer an issue. Testing the recoil, the Elite found it to be slightly concerning, but felt that for all intents and purposes, wouldn't hinder them, as they needed to be conservative about their ammunition, even if looting it from the corpses of their foes.

An elderly man, who looked fit for military service, attempted to sneak up on an isolated Elite, and end his life with the laspistol her had in hand. He was fit, but not accurate, and had to get close. But he got too close. The Elite turned around, and instead of shooting with his **Overwatch Standard Issue Pulse Rifle**, OSIPR, but grabbed the man by his throat, raising him into the air with a single arm, and looked at him squirming with his single ocular lens. Before pulverizing his neck with his hand alone. Throwing him down at the ground, he made sure the citizens around him could see what he, they, were capable of doing. But Overwatch conditioning alone couldn't give them strength of that magnitude. A few of the soldiers that were somewhere near the Elite had been wounded and miraculously not killed in a hail of bullets. One of the other soldiers, armed with a shotgun, handed each of them a single green vial.

"Overwatch has issued new orders. All units are to be preserved at all costs. 3cc shots are authorized, but 15cc packs fall under X-RAY Command juridstiction and are to be primarily used on Synth units."

"Copy. 3cc shots will be used in emergencies, correct?"

"Affirmative. Distribution will be done and overseen by X-RAY units."

* * *

The eighty Gunships were left a free reign. Ahead of the escort fighters, the Gunships made their way to the general location of the energy radiation rather quickly, meeting slight opposition as they dodged their shots with swift ease. Once there, they bore witness to a bloody battle. Men clad in golden armour fighting those seen earlier when the scouting forces landed. Ordinarily, this would be glossed over, and the Gunships would simply destroy any and all stationary defenses that proved dangerous, alas, this influx of hostiles pouring into the palace-like structure would prove more dangerous. The Gunships split off into four groups, twenty each, as to combat these invading hostiles. One of the groups was dispatched into the area of highest fighting, something that would come to be known as _Eternity Gate_. The fighting below slowed down ever so slightly as the troops below heard the howls of three of the Gunships, giving the Gunships enough time to disperse optimally, moving in a circular formation, switching places with each other, and one occasionally turning around as to shoot down the odd rocket that tried to hit one of them, before they all opened fire in unison.

Their bullets, at first, bounced off the armour, but soon it started penetrating, and injuring some of them, killing few. This wouldn't be enough it would seem. A manifest had to be made. Ten of the Gunships positioned themselves directly above the invading hostiles as they continued fighting the men in gold, with the other ten providing cover for their 'comrades' if one could even call them that. As they hovered in place, they began charging up their circular cannons located on their underbellies, before firing them in all their glory. Blue-ish beams of energy came crushing down at the men in black armour, halting them, killing them, and disintegrating them. This had the defenders severely confused - just enough for the seven Heavy Dropships to sneak past most defenses and land, allowing the Tylox-class Heavy Fighters to focus on ground support.

As soon as they had landed, fifteen meter tall bio-mechanical constructs emerged, a total of six now. Armed with devastating Dark Energy cannons in one hand and armor piercing guns on the other, they formed a defensive perimeter around the seventh Heavy Dropship, their four armored legs destroying the metal below as to entrench themselves. The fabled 'Children of Arkyon' had arrived, each sporting up to three meter thick armor. However, there were openings in this armor that revealed withered bodies of unknown creatures, blood and green ooze dripping from the arms and the backs, implying that they were rushed to be made prior to deployment. As faithful defenders of the mighty palace clashed with the Children of Arkyon, out from the seventh Heavy Dropship came an anti-gravity carrier, containing countless mechanical arms, pieces of what would look like a device, alongside Dark Energy Fusion Cores to power it.

As it finally came out, the mechanical arms burst to life, starting the assembly of nothing less than a Tunneling Entanglement Device, however, far weaker than its Citadel counterparts. While assembly was underway, one of the Children of Arkyon screeched: its body, actual body, was hit. The screech was mangled and warped by the machinery it was connected to, but it soon quieted down, continuing to barrage whoever posed a threat. By the time they were set up, the Gunships, seeing as a distraction was no longer necessary, came to the aid of this miniature base of operations, with three dying on the way back, engulfed in flames and in pieces, leaving seventy-seven in total alive. Not long after, minutes before assembly was completed, an announcement came through from the Overworld, to send out further orders to the soldiers.

"Attention all personnel, this is the Head of Union Security speaking on an encrypted channel, do not respond. Once the portal is open at the assembly area, we will send Stalkers and Synth Super Soldiers to gain access to one of the terminals of the enemy. After that, any and all information they gather on the whereabouts of this 'Emperor' is to be relayed directly to the Supreme Overlord and I, so that we may send adequate forces to deal with him, paving the way for a potential conquest of the planet by breaking morale. Group 1, Section 1, you are about to be encircled. Evacuation is advised as soon as possible. If you can make it to the assembly area, you will continue fighting. Otherwise direct yourselves to the mega-portal that opened itself. Sector 1, establish Sectorial Command and begin pushing outwards. I leave it to Sectorial Command to establish a chain-of-command. Out."

* * *

It was a grim time to be attacking or defending the Imperial Palace, as hordes upon hordes of both Daemons and Traitor Legions clashed with the defending Loyalists and Custodes. All but few were oblivious to events happening on the lower plateaus of the Imperial Palace, as xenos come forth from a singular portal, reminiscent of the Eldar and their Webway Gates, yet different in their own unique way. For truly, these were no Eldar, or Dark Eldar, no. These were the legions of an unidentified xenos race with sophisticated technologies that warrant attention from the Adepts of Mars, military discipline that the Legio Astartes would respect, and determination that is on par with that of the Emperor and his titanic patience.

Shield-Captain Prefect Arganus Stormbringer made first contact with the unknown xenos, prompting him to act swiftly. However, acting without information on how they worked, or even what their goal was, is, and always will be, the downfall of many. He turned to his aide and comrade, Imperial Fists Space Marine, Torviak Phomedes, for advice on the topic of the first step in dealing with the xenos threat.

"What say you, Torviak? Is it wise to see what the xenos want before we act?"

"It is hard to say. These xenos may only want information, lest they would have came with a bigger force."

"You make a valid point. I shall see how strong their resolve and guns are for the time being."

"And I shall make sure the **Mechanicum** and I prepare proper defenses, should they attempt to penetrate into the Palace."

With all said, and the plan in motion, all that was left to do was wait for the xenos to make their first move. The Custodians clashed with them from a distance, to no avail, as their armour was too thick to penetrate. Yet, not all was in vain, for the brutes in armour could be wounded, and if they could be wounded, they could be killed. One of the Custodians was hit directly in the chest by a blast from the xeno weapon, firing a very bright blue bolt of energy, which had disintegrated the weapon he held as it very quickly bounced off the chest armour. The xenos had received support from the air, prompting the Shield-Captain to withdraw his forces to a safer defensive position, one that obstructs the line-of-sight for the aerial forces.

The Shield-Captain was soon after approached by one of the Adepts of Mars, who brought troubling news.

"Adept, you wish to say something?"

"Indeed, lord. I could not find the Captain-General, thus I ask of you to relay this to him. This new xenos force that has appeared on Terra came not by ships, but by a portal of immense magnitude and power. However, they either cannot maintain its size or keep it powered up for long periods of time, due to it constantly shrinking. By my estimates, it is approximately 72% of its original size, and shall disappear wholly within 9 hours."

"By Terra... have you detected any other signatures of similar kind?"

"I have, yet it is far weaker than the primary power signature. However, its power fluctuations are within stable parameters according to readings I and the other Adepts have conducted. They are bringing in reinforcements."

This had the Shield-Captain simply stare at the line of defense. If reinforcements could come from the other side, then they could storm the Imperial Palace en masse, or even the whole of Terra. The fact that they do not wish to attack just yet suggests that very possibility. The main gate to the palace was charged by the traitors, and that was where the Captain-General had to be. He needed to deliver the message he received, but abandoning command of this section of the Imperial Palace would leave the xenos unchecked, even if he gave control to Phomedes. It would be best to send someone else to report to the Captain-General, Arganus was sure of it. Approaching one of the only entrances to the Imperial Palace from the lower plateaus, he saw the Mechanicum and Phomedes working tirelessly to erect fortifications.

Phomedes stopped, seeing the Custodian approaching him, troubled by something.

"Something troubles you?"

"Indeed. I need you to deliver a message to the Captain-General, he is most likely at Eternity Gate, if not, he is in the Throne Room."

"This message being?"

"The xenos on the lower plateaus have two portals fully functional, one is closing while the other is not. Tell him that should things go for the worse, I will need reinforcements."

Phomedes looked stunned for a moment, coming to terms with the xenos potentially swarming Terra. Yet, snapping out of the initial revalation, he gave Arganus his word that he would deliver the message post haste, before taking his leave. By the time Arganus returned to the line held by the other Custodians, he could see an opening in the xenos lines, and, albeit faintly, the portal through which came disfigured persons whom had been stripped of all life, as well as heavily armoured xenos soldiers, similar in size to the Astartes. And as the last of them went through, he could see what can only be described as Hell incarnate on the other side of the portal. He ordered the Custodians to make a tactical withdrawal to the fortifications, for ease of defense and to minimize casualties. As they withdrew, they saw the Astartes-like soldiers start to advance, the disfigured humans in tow behind them.

* * *

The Synth Super Soldiers pushed onwards, protecting the Stalkers as they made their way to the interior of the palace. An order had been issued by Sector Command to the Throne World to send additional forces, to which the Throne World responded by sending another fabrication unit, alongside schematics for a Biological Development Unit and parts for a Synth Fabricator. The ScL made a decision to expand the perimeter tenfold in order to have place for the Synth fabricator to be built. Creatures needed for the Synth production would be of lessened strength due to the Biological Development Unit, but could be made much faster. For speed in this short campaign was crucial. Dispersing the Children of Arkyon, or how they're officially known as Reclamator-class Heavy Synths, he increased the perimeter tenfold, using some of the Super Soldiers to fill in gaps in the defensive lines.

Anti-grav carrier units came through the portal at a steady pace, carrying the materials needed for the Synth Fabricator, as well as for any Synth made within. The ScL noted that the Throne World wasn't sending anything needed for Heavy Synths, which means they expect the job to be done very soon. He would have complained if he could, but the will of the Throne World was absolute.

The Overwatch ScL was approached by one of his comrades, a DvL equipped with one of the guns of the enemy, the so called 'Bolter'.

"Sir, political conscripts report that non-citizens have detected us on visuals in orbit. A single craft is preparing to commit to a vaccination of our immediate 10-20."

"Copy, DvL. Prepare stabilization delegates for breach with Synthwatch, shield political conscripts and clamp non-citizens. Verdict status?"

"300 verdicts, 100 verdicts for each Bolter, sir. Recommending use of chemical weaponry to eliminate non-citizens."

"Recommendation noted, DvL. Will dispatch to Overwatch and request 5 Tachyon-class Terraformers."

The DvL was quick to take his leave after the ScL's acknowledgement. The soldier continued monitoring the situation from one of the terminals that had been set up in the makeshift base, sending out orders to different units simultaneously. He noted that the original expeditionary forces were almost entirely obliderated, Striders disintegrated from weapons overloads and stabilization delegates decapitated, dismembered or completely pulverized in some cases. Only fifty OTA Elites had managed to survive and get onto the Dropships, as all of them had left for the portal.

Those foolish enough to follow them quickly found out just how powerful the Throne World's defensive systems were. Several Thunderhawks foolishly followed them to the other side, instantly getting shot at.

* * *

"Sir, the Thunderhawk can't take much more, and it has only took one whole volley from the enemy!"

Screamed a space marine of the **XIX Legion**, the **Raven Guard **as he tried to stabilize the Thunderhawk. His battle brothers could only do so much to mitigate the damage before they too started dying. As the second volley of these unknown xenos guns fired and collided with the Thunderhawk, it was forced to return through the portal and back to Terra. One of the four Thunderhawks that had crossed through went up in flames and exploded, colliding with the large black metallic monolith, leaving only three Raven Guard Thunderhawks left. Two were critically damaged, and had to land as soon as possible, prompting them to land at the Imperial Palace. If they were to crash-land anywhere, it would be where the thickest of the fight was going on. And so, the Raven Guard space marines braced for impact, the Thunderhawks slowly dying out as smoke filled the air, the engines giving out just as they had reached the lower plateaus.

The doors of the two crash-landed Thunderhawks were pried open, and the Raven Guard burst forth, forty-eight of the battle hardened Astartes taking cover behind what debris they could find, expecting to see their fallen brothers. To their surprise, they saw a line of marching xenos, inhuman and human, approaching the Imperial Palace interior. Amongst some of the xenos were machines the size of a Dreadnought, with strange cylinders on their backs, propelling themselves with gasses, if the fumes coming out from them were anything to go by. Mighty legs that break the ground below them ever so slightly propel the beast of metal forwards, with what substituted as guns scanning for targets, as if they had a life of their own.

"Brother Captain, they come for the Palace. We must intervene." A Space Marine said to his superior. Captain Rostrum Acutum of the Raven Guard weighed his options carefully. A head-on assault without reinforcements was suicide, even for Astartes. Picking them off from the shadows, although preferable, was worthless in the grand scheme of things, for they would surely penetrate the defenses of the Custodes before their numbers dwindle to a sufficient state to where a counter-attack was possible.

"Nay, brother. We must let them proceed to crush them, for they shall not expect retribution from their rear. Scavenge whatever you can to make better defensive positions, for I expect not these forces to be the only ones to come." It wasn't a popular decision, but a necessary one, which his brothers understood. Doing their best to remain out of the enemy's notice, it took them hours to finally complete all preparations. They went forth, twenty-four of them to the enemy's headquarters, the other twenty-four to the enemy's main strike force. Rostrum went with the first team, eyeing the enemy's defenses critically. Black walls litter the lower plateau, spotlights searching for anything and anyone that isn't one of their own, abominations of flesh and machine patrolling outside, and the main gate open to let out the myriad of forces exit the stronghold. All of them three-legged, varying in size, some blue ones almost the size of an Astartes, and the other ones towering over them all with their frail exo-skeleton protecting the mushy insides of the beasts.

The Astartes soon overheard the steady beat of klaxons activating, and a faint sound of gun emplacements rotating into position. Theoretical: it was anti-air cannons. Logical: something threathened them greatly. And it was a sight to behold, as their brothers descend from orbit, met by the hail of gunfire from anti-air turrets of the xenos, spinning their gyros hap-hazardly, working themselves to the bone in order to shoot down all the anomalies in the air that descend upon them. The first of the drop pods to land revealed a formidable ally indeed, for it was an Ultramarine Dreadnought. Its landing knocked down five of the smaller xenos, but failed to kill them, which was cause for respect, for not many survive the initial shockwave of a drop pod landing so close to them.

The smaller xenos recovered quickly, releasing sounds akin to howls, low and high pitched. Their maneuverability was great, and oddly natural given their forms. This in turn attracted the other, taller ones, slowly striding towards the area of combat. They all fired, the small ones firing flechettes, which just barely stuck to the armour of the Raven Guard, releasing small explosions upon attempted removal and after a short period of time. Rostrum and his men made elegant moves, supported by the heavy weaponry of their Ultramarine ally, with Rostrum bringing down his Power Claw unto the soulless Xenos, almost cutting it in half from top to bottom. The creature released a furious screech, ultimately collapsing into a mush, its insides shown for all to see: wiring running all around the grey matter of the creature, parts of the brain replaced with metallic slates of combat stimulants connected to injectors found further inside the brain, connected to individual neurons.

Some more drop pods landed, revealing more Ultramarines, this time being ordinary Battle Brothers, six of them to be precise, lending surpressing fire for the Raven Guard, and using the debris around them and the drop pods themselves as cover. As Rostrum cut past three other xenos, one even attempting to charge him, he was struck in the shoulder by an oversized needle, penetrating the Ceramite and landing into flesh. He scanned the surroundings for the assailant, but found nothing different. Theoretical: the enemy was at a longer range. Logical: the enemy had cloaking technology. Whatever the answer, he was content with him being the first to be struck.

"Brothers, the enemy possesses long-ranged units! Proceed with caution!" He commanded, the rest of the Raven Guard and even the Ultramarines obeying, now alert for the unseen enemy. They moved swiftly, now starting to converge on the tall xenos. To their credit, the tall ones had the strength to not only stop an Astartes dead in his tracks, but to even penetrate Ceramite in a devastating impale. That same impale, however, costs them mobility and valuable time. The Bolters did not pierce the exo-skeleton immediately, but in time, the Bolts found themselves lodged deeply within the brains of the beasts, sending them crashing to the ground. Something moved past the portal inside the base, Rostrum and some of his brothers using the distraction to enter. More and more Ultramarines joined them, but it was getting close: the second group that Rostrum had sent to deal with the attackers was forced to withdraw, even the Astartes being affected by some kind of toxic gas fired off by the white coloured goliaths.

The four of them saw a levitating grub-like entity, gas mask on its supposed face, metallic arms, optics on the lower left cheek, and four antennae on its back. It was moving towards a ship that they had previously not seen, the ship beginning to power its engines, releasing a low hum. They had tried sneaking up to it, for it did not spot them the first time, and succeeded. As it was about to get inside of the transport, one of the Raven Guard charged it, Power Claw at the ready, except... he never got to slice the grub in half. It turned around on time, stopping the Astartes mid-air, and as the four antennae lit up, the Astartes surpressed the urge to scream as Ceramite bended, crushed under an unseen weight, flesh tore open by the fragments and bones broken from the sheer force it had to endure. Rostrum tried to intervene, only to find himself and his brothers pinned down by enemies within the transport. The now dead Astartes was flung into a group of enemy soldiers unknowingly, killing them on the spot, allowing the grub to enter the transport. The last he saw of it was the ship lifting into the air...

The Raven Guard had by that time gone as far as they could from the makeshift base, due to one of the Battle Barges above preparing to bomb it from orbit, with limited precision and effectiveness. But, for all intents and purposes, it would be enough. Some of the enemies had passed through, most notably the attacking group that went into the Imperial Palace, but all others were boiled alive by the heat of projectiles raining down unto them, unlucky ones killed by the later explosions. This, was a victory for the Imperium. The battle was short, but many more were to come.

* * *

In but a few moments, **Sanguinius**, Primarch of the **IX Legion**, the **Blood Angels**, and one of the sons of the Emperor of Mankind, lay dead. His killer, Horus Lupercal, stood proud over the corpse of his brother, staring at his father in disgust. He swore allegiance to the Chaos Gods, and was determined to kill his own father, and erase all of his achievements throughout the millenia. The Sons of Horus Space Marines fought with what was left of the Blood Angels Space Marines that Sanguinius had brought to aid his father in attempting to subdue Horus, alas, some were relegated to guarding the massive chamber in which the two were to have their final confrontation, for unknown and unwanted intruders had made it onto the ship.

For all the strength the Sons of Horus posessed, they were outmatched by monstrosities all too similar to ancient evils that once ruled the galaxy. Taking entire hallways, they looked like an impenetrable wall of pure Adamantium and Ceramite, whilst carrying powered Gauss Rifles: something that had been, surprisingly, deemed as more effective than Dark Energy when fighting against Space Marines. And indeed they were walls, sized so perfectly to the halls of the ship that it had left their backsides extremely vulnerable. The Children of Arkyon were never intended to unfold their armour as to make a wall, yet it still worked as intended, since it protected their frail and fragile bodies from harm. As the majority of the bodies had been exposed, it allowed for the blood and green ooze to leave a solid trail on the floors below, making tracking them as easy as helping a small child retrieve his cat from the tree, and then skinning it in front of them. In the very middle of the column was an Advisor, no different than his brethren, save for having four antennae on his backside, implying that he was a lieutenant to the Head of Union Security, one of many that he had.

Finally, after a long amount of time passed, they were in the room where the Emperor was. They had him in their sights. As the Children of Arkyon entered, their armour folding back into position, they started charging their Gauss Rifles, preparing to deal a finishing blow, utterly crushing morale for at least one enemy. Horus and the Emperor clashed, the Emperor obviously holding back, thinking that his beloved son can be redeemed. It was at that precise moment that he had to witness the death of his second child, his most beloved Horus Lupercal. As it turned out, the Gauss Rifles fired off just as Horus stood in front of the Emperor, prepared to deal the finishing blow, blowing a hole in the armour, and immobilizing him. They wasted no time to secure the corpse, as the Advisor saw an opportunity for redemption. The Emperor shall live this day, but his Imperium will suffer greatly over the course of years that have yet to come. While the Children of Arkyon made their way to Horus, the Emperor tried one last time to persuade his son to stop with this madness that he had caused.

"Horus, you need not continue this madness! Return with me, and all will be forgiven!"

"If only you understood the hatred I have for you! You and your infallable vision have brought about my righteous crusade against you! The Imperium needs a leader that listens to others, not one that listens only to himself! Not one that shall bring ruin to mankind!"

Attempting to fathom the words his son spoke out, the Emperor had to focus on the fight here and now. He had dodged shot after shot of Bolters and Gauss Rifles, impaling one of the Children of Arkyon through one of the openings, only narrowing his eyes in response to its mangled shriek of pain. But dealing with them and the traitor Marines was only part of the Advisor's plan. Suddenly, around Horus and it, the metal bended, forming a barrier between them and everyone present. Horus stared at the xenos abomination, swearing at it, and swearing at the Emperor for his defeat. And it... it stared back. Using great effort to lift Horus up sufficiently, the Advisor prepared for any trick the Warmaster had at his disposal. Sensing that he is too weak to fight back properly from the wound inflicted, the Advisor slowly lifted the breathing apparatus, and extended its tongue. Spinning the Warmaster around, the tongue touched the neck multiple times after bending the armour sufficiently, and impaled at the nape. It made motions similar to sucking something out, before the tongue returned into the mouthe, breathing apparatus back on, and the Warmaster dead, on the floor. By the time it started fleeing at great speeds, the Emperor had dealt with the Children of Arkyon and beat back most of the traitor Marines with only five Blood Angels Space Marines remaining. They gave chase, but to no avail, for the Advisor was faster than they were, and was long gone. One of the Space Marines turned to face his Emperor, as both looked shocked.

"My lord... our Primarch, Sanguinius..."

"I know. I see now the fault that I had made, even before the final duel between Horus and I. We shall converse on Terra once we escape the Vengeful Spirit. Come forth, for we must return to the surface."

It was only then that one of the Blood Angels noticed a lone soldier inside the room, battered lasgun in hand and with his Army uniform on. Soon after, the Emperor took notice alongside the rest of the Blood Angels, and one of the Custodes that had been done fighting on another area of the ship.

"A trooper such as yourself is brave indeed for coming here in the midst of a treachery of massive scale. May I have your name?"

"Ollanius Pius, my Emperor. I had recently gotten into this room, just as the arch-traitor was to deliver a potentially fatal blow. If only those damn xenos didn't come and wound him, I would have made the ultimate sacrifice to preserve you."

"I see now that your bravery knows no bounds, Ollanius Pius. Come now, for we must return to the Imperial Palace before the traitors send us all into the Warp."

* * *

"Not only have you failed in securing a permanent foothold on Earth, you have also failed in killing the Emperor of Mankind."

The Head of Union Security spoke to his lieutenant, who had cowered from sharing the information with his superior that would reveal his utter failure. He did however share the information of killing someone close to the Emperor. Although he could feel that his superior was pleased, he did know that a punishment nonetheless awaited him.

"How very good of you. And you have everything he knew... I will send word that you died in a very _unfortunate_ accident."

Moments after the Head of Union Security spoke out those words, his tongue pierced his lieutenant's head area, before retracting several seconds later. The Advisor slumped to the ground, as his superior wiggled in the air, processing the plethora of new information that he had gathered from penetrating his subordinate's cranium and devouring the neurons and grey matter within.

"This is quite a lot of information. Holding all of it truly is remarkable. Now, to pitch in the idea of repeat invasions to the Supreme Overlord... however." The Advisor stopped mid-way, turning towards a particularly dark corner, seeing a faint glow of optics "Dyatlov, you can stop hiding."

"I prefer to stay in the shadows for now." Dyatlov spoke, his own voice modulator glitching, giving off a sickening growl-like voice at one moment, and a sweet and innocent one another. "Do you think the time dilation we had caused will reach this new location?"

"Assuming it hasn't already, Dyatlov. It affected not only our space, but dimensions adjacent to our own. Continue monitoring the galaxy, however, for we will be returning."

* * *

**Author's Note: And now, onto the topic of the day.**

**Welcome, ladies and gentlemen to how the Combine screwed everything up. Not really much changed, except a few things here and there. I might not have gotten everything right, and please do point that out! Every critique, good or bad, helps the story! As you can see, the Combine have custom technology, which is needed to actually compete with the Imperium, since what we know is just... no. To address the recurring character of the Head of Union Security, I can safely assure you that this story is connected with 'The Light of Remnant' and every other half-life crossover I plan on making, essentially making it one gigantic series of stories. Also, do NOT expect these to come out a month after the other consistently. Some chapters may require more study and fact-checking on my end to provide the best alternate 40k experience for the reader, and the length of these chapters will play a role in how long it takes me to release a new one. So if I don't post a new chapter in 3 months, expect it to be good (unless it isn't in which case you can throw me into the Eye of Terror. In which case I send the Blood Ravens to steal all your Gellar Fields).**

**Well, that'd be it for now. Adios, amigos. New chapter will come out as soon as it can!**


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